Apparatus and method for gating with diaphragm packing machines



July 22, 1958 Filed March 5,4 1957 K. E. DAvls 2,843,893 APPARATUS ANDMETHOD FOR GATING wTH DIAPHRAGM PACKING MACHINES 2 Sheets-Sheet 1 FIG iINVENTOR KenneH/m-Davis ATTORNEY K. E. DAVIS 4 H FOR GATING WITHDIAPHRAGM PA NG MACHINES 2 Sheets-Sheet 2 INVENTOR Kermeh E Davis,

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ATTORNEY July 22, 19.58

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APPARATUS AND METHOD FOR GATING WITH DIAPHRAGM PACKING MACHINES KennethE. Davis, Grosse Pointe Woods, Mich., assignor to The Budd Company,Philadelphia, Pa., a corporation of Pennsylvania Application March 5,1957, Serial No. 644,039

9 Claims. (Cl. 22-38) This invention relates to apparatus and method forgating molds which arepacked by diaphragm packing machines such as thosedisclosed in the patents to Taccone 2,698,976 and 2,715,758, morespecifically for forming a sprue hole and pouring cavity or cuptherefor, and has for an object the provision of improvements in thisart.

When asks are packed by diaphragms there is considerable ditculty informing suitable gate sprues and Acups in the sand. Several methods havebeen tried but all have given much trouble. It is not necessary to noteall prior methods and their shortcomings but a couple may be mentionedby way of example.

One method has been to pack a solid body of sand and later to bore outthe sprue and cup. This obviously leaves loose sand at the surface whichwill wash down with the metal during pouring.

Another method is to provide a cupforming protuberance on the lower sideof the diaphragm but since the diaphragm is a loose sheetthe-protuberance is likely to assume various positions and dispositionsother than the one intended.

According to the present invention an extremely simple form of apparatusand procedure are provided which produce in the diaphragm packingoperation an accurately formed sprue and cup with a smooth packedsurface `free from sand and without the need for any secondaryoperations.

The invention will be explained in connection with the accompanyingdrawings showing an illustrative embodiment thereof wherein:

Fig. 1 is a vertical sectional view through a packing machine and a moldpart showing the parts after a packing operation has been completed, theview being taken on the line 1-1 of Fig. 3;

Fig. 2 is a partial sectional view of the mold part after the sprue andcup opening have been cleared of sand;

Fig. 3 is a top plan view taken on the line 3-3 of Fig. l before sand isdeposited in the mold part; and

Fig. 4 is a vertical section through a full mold assembly after a parthas been cast therein.

For illustrative purposes it will be assumed (Fig. 4) that a wheel brakedrum is to be cast on a supporting disk 11. In Fig. 4 there is shown aiiask, or mold comprising a drag 12 and a cope 13 with the cast drumtherein. The present invention is concerned with the packing of the bodyof sand 14 in the cope and the formation of a gate 15, sprue 16 andsprue cup or cavity 17 in this body of packed sand. The entire channelmay be referred to as a gate.

The usual apparatus with which the present invention is associatedcomprises a press frame 20 having a base 21 and a pressure head 22carrying a diaphragm, bladder or obtruder 23 below a cavity 24. Meansare provided for introducing lluid under pressure into the cavity topack sand in a cope 13 positioned therebelow or to create a vacuum towithdraw Ithe diaphragm after the sand has been packed.

United States Patent i 2,843,893 Patented July 22, 1958 ICC A pattern 27is carried on the base 21 and the cope 13 is positioned over thispattern, suitable means, such as pins, being provided to insure properregistry of parts. The pattern and cope are arranged to be moved in andout from beneath the pressure head 22 for assembly and separation. Thecope is first iilled with sand above the pattern and levelled with thetop of the cope. Then an open ring frame 28 to laterally confine thediaphragm is placed on top of the cope, suitable positional registrymeans being provided. The ring frame may be placed first if more sand isneeded. Then the assembly is moved on the base to a proper registryposition beneath the head. A sprue pin 30 is slidably carried by thepattern member. The pin is provided with means such as a shoulder 31 tolimit its down position but its lower end is accessible through thelower end of the hole in the pattern piece so that it may be pushedupward a short distance. The sprue pin, like the pattern, has suitabletaper to provide easy separation from the packed sand when the cope andpattern are separated.

According to the present invention there is provided above the spruepin, where the gate cup cavity is to be formed, a circumferential frameor barrier support 32 which locally supports the diaphragm to pre-vent-downward movement along this circumferential line.v In the formillustrated the cope frame itself forms part of this barrier support. Asa consequence of this local circumferential support, the diaphragm underpressure takes a concave shape with the pointed bottom of the concavityabove the end of the sprue pin. By making the upper end of the sprue pinrounded there will be only a thin layer of sand left on it afterthepacking operation.

After packing, the sprue pin is pushed up from below by hand, as shownin Fig. 2, or by coordinated mechanism if an automatic machine isprovided., to break away the light sand layer between the cup and sprueand the loose sand in the space is blown clear by an air jet in knownmanner.

As shown, the gate pocket or cup and the main top surface of the sandare near the same height. Actually the diaphragm will press more deeplyinto the sand at the cup location because of the smaller concave shapewhich the diaphragm is caused to take there as compared to the broadouter surface elsewhere. The sprue pin effectively stops the downwardmovement of the pointed protrusion of the diaphragm so that the cupdepth will be regulated. The sloping sides are firmly packed so `that noloose sand is present to be entrained with the metal.

If it is desired that there be a difference in bottom level between thecup and the outside area this can readily be regulated by adding ortaking away a certain amount of sand in the cup enclosure after the sandin the cope has been initially levelled olf.

It is thus seen that the invention provides very simple and eiiectivemeans and method for forming gate cup and sprue shapes in diaphragmpacked molds.

While one embodiment of the invention has been described for purposes ofillustration it is to bev understood that there may be variousembodiments and modifica tions within the general scope of theinvention.

What is claimed is:

1. Molding apparatus for forming a gate cup in the sand in a mold partby means of a sand packing diaphragm, comprising in combination with thepress and diaphragm and the mold part, of a barrier frame arranged inthe mold part at the gate cup location for supporting the diaphragm in acircumferential line to cause it to press the sand within the barrierframe to form a gate concavity with sloping sides in the sand as itpacks the sand in the mold part.

2. Molding apparatus for forming a gate cup in the sand in a mold partby means of a sand packing diaphragm, comprising in combination with thepress and diaphragm and the mold part frame, of a barrier loop framearranged in the mold part extending inward from the side of the moldpart frame and forming with it a closed loop for supporting thediaphragm in a circumferential line to cause it to press the sand withinthe barrier frame to form a gate concavity with sloping sides in thesand as it packs the sand in the mold part.

3. Molding apparatus as set forth in claim 1, wherein said barrier frameis of less depth than the depth of the mold part to allow sand to packtogether beneath it.

4. Molding apparatus as set forth in claim 1, which further includes anempty frame arranged on top of the mold part to conne the diaphragmlaterally.

5. Molding apparatus as set forth in claim 1, which further includes asprue-forming pin located at the lower end of the gate concavity formedby the diaphragm.

6. Molding apparatus as set forth in claim 1, which further includes asprue-forming pin with a convex upper end located at the lower end ofthe gate concavity formed by the diaphragm.

7. Molding apparatus as set forth in claim 1, which further includes asprue-forming pin mounted for vertical movement at the lower end of thegate concavity formed by the diaphragm.

8. The method of forming a gate cup in the sand in a mold frame by asand packing diaphragm which comprises, providing sand in a mold framehaving an inner diaphragm-supporting frame within the mold frame abovethe zone where the gate cup and sprue hole are to be formed supportingthe diaphragm on the inner frame in a circumferential line around theupper end of the gate cup location, and applying fluid pressure on thediaphragm to cause it to form a gate cup concavity with sloping sideswithin the line of support on the inner frame while packing sand in themold frame.

9. The method of forming a gate cup and sprue hole in the sand in a moldframe in a diaphragm-type packing device which comprises, supporting thediaphragm in an interior circumferential line around the upper end ofthe gate cup and sprue location of a mold frame filled with sand,arranging a vertically movable sprue-forming pin in the bottom of thegate cup concavity location, applying iluid pressure on the diaphragm tocause it to form a gate concavity with sloping sides within the interiorline of support while packing sand in the mold part, the packing actionleaving a layer ofv sand above the end of the sprue-forming pin, movingthe pin upward to break the sand layer over its end, and later blowingloose sand out of the gate and sprue.

References Cited in the file of this patent UNITED STATES PATENTS322,203 Rice .Tuly 14, 1885 408,386 Moore Aug. 6, 1889 2,767,446 PrayOct. 23, 1956 FOREIGN PATENTS 750,979 Great Britain June 20, 1956

